Concrete Filled, Fiber Reinforced Polymer (FRP) Composite Tubes Bridge-in-a-Backpack A collaborative innovation together with:
Fiber Composite + Concrete Arch Superstructure A Hybrid bridge system combining benefits of high-performance composites with durability and cost savings of cast-in-place concrete Image Credit NY Times/University of Maine
Innovation. UMaine AEWC Composites Center 87,000 ft 2 facility Researching Hybrid Composite Systems since 1996 Nearly 12 years development of Bridge-in-a-Backpack Secretary of Transportation Ray LaHood Speaks about Bridge-in-a-Backpack at UMaine Press Event
National Recognition for Bridge-in-a-Backpack AASHTO TIG - 2011 Focus Technology 2010 Award for Composites Excellence Most Creative Application American Society of Civil Engineers 2011 Charles Pankow Award for Innovation Engineering Excellence Award Royal River Bridge, Auburn, ME (Along with Maine DOT & Kleinfelder SEA) Product featured in: Engineering News Record, The NY Times, Concrete International, Popular Science, Popular Mechanics, The Boston Globe
- Develop & patent manufacturing process - Model development - Structural testing - Model refinement - Material optimization - Demonstration project - System refinement - 2001 2005 2008 Ongoing Manufacturing of 60 Span Arch Arch Structural Testing
Deflections measured using 3D digital image correlation system FE model predictions compared with experimental response Arch Deflected Shape, Experimental and Predicted (Deflections Magnified 15X) 30 P 10 DIC Targets -10 Location (in) -30-50 -70-90 Predicted Experimental -110-140 -120-100 -80-60 -40-20 0 20 40 60 80 100 120 140 Location (in)
1. Stay-in-place form for concrete Temporary Formwork for Arches Concrete Engineers Handbook, McGraw-Hill, 1918 Arches and decking are the only formwork needed to stabilize the structure Eliminates need for temporary formwork
Three Functions of the FRP Arch Tube 2. Structural reinforcement for concrete confinement Confined Unconfined Three Components of FRP Reinforcement Confined concrete demonstrates significant ductility over unconfined Eliminates need for rebar installation, no steel rebar in superstructure Enhances concrete performance for safety & structural redundancy
3. Environmental protection for concrete Steel rusts and expands causing concrete spalling Spalling concrete exposes more reinforcement Concrete Corrosion Cycle Photo Credit: Bridge with Sky thanks to John Hillman and MoDOT Drastically reduces maintenance requirements
Load-Deflection Response of Concrete-Filled FRP Tubular Arch 80 70 60 Applied Load (kip) 50 40 30 HL-93 Design Load Equivalent 20 10 0 0 1 2 3 4 5 6 7 8 9 10 Vertical Deflection at Crown (in) Initial Static Test to Failure
Experimental & Predicted Capacity Failure Load (kip) COV No. Percent Diff. Initial Secondary Experimental 72.0 2.55% 3 Predicted 69.0 -------- -------- Experimental 57.6 7.75% 3 Predicted 57.0 -------- -------- 4.14% 1.10% Load-Deflection Response of Concrete-Filled FRP Tubular Arch 80 Initial hinge at crown 70 60 Applied Load (kip) 50 40 30 20 Subsequent hinges at shoulders 10 0 0 1 2 3 4 5 6 7 8 9 10 Vertical Deflection at Crown (in) Initial Static Test to Failure Post-Failure Behavior
Load-Deflection Response of Concrete-Filled FRP Tubular Arch 80 70 60 Applied Load (kip) 50 40 30 20 HL-93 Design Load Equivalent 10 0 0 1 2 3 4 5 6 7 8 9 10 Vertical Deflection at Crown (in) Initial Static Test to Failure Post-Failure Behavior
Our shared R&D Center at UMAINE Russian Engineers from the Federation Railway System representing 11 other countries as well
Arch Formwork 1. Tubes assembled/packaged 2. Inflate tubes 3. Bend around arch form 4. Infuse with resin Manufacturing of a 15 diameter 48 span composite arch Within hours, arches can be removed from form for installation
AIT s arches arrive on site ready for installation Can be unloaded quickly with hand labor HEAVY TRUCKS
Filled with Self Consolidating Concrete (SCC) Simple procedure, no rodding/vibration required AIT provides standard specifications for concrete mix Pumping concrete into arches Funnel boxes direct flow, prevent overflow
SCC is a concrete that uses High Range Water Reducers (HRWR), or superplasticizers, to achieve high flowability In our mix we also include Hydration Stabilizer (retarder) Shrinkage Compensating Admixture (SCA) 3/8 pea stone aggregate Aggregates evenly distributed throughout spread No bleed water at leading edge ASTM C1611 Slump Flow
Proposed AASHTO LRFD Guide Specifications for Design of Concrete-Filled FRP Tubes for Flexural and Axial Members Closed-form, simplified method for design of Concrete-Filled FRP Tubes (CFFT s) Bending (φmn), Axial (φpn), Shear (φvn) Combined Axial and Bending (interaction diagrams) Connection detailing Generic in nature applies to all CFFT s Presented to AASHTO s T-6 (FRP) Committee in May 2011 T-6 plans to put forward for ballot to SCOBS in July 2012
Design Options Numerous Applications Highly Customizable Geometries Spans up to 75 Single or Multiple Spans Skewed designs Standard geometries or customized for specific sites Deep soil cover (45 and greater) Water/stream crossings, Roadway overpass/underpass, Railway, Pedestrian, Tunnels Inexpensive, Quick Installation, Long-term Reliability
Multiple options to meet the Engineering, Economic, and Aesthetic requirements of the site FRP Panel Walls MSE or Through-Tied Configurations Compatible with skewed bridges Lightweight, easy to install Durable, and cost competitive Concrete Precast or CIP MSE, Through-Tied, or Gravity PC Panel, PCMG Units, Cast-inplace Versatile design options More conventional aesthetic
Architectural facades, details, rails, can be incorporated for improved aesthetic qualities Images courtesy of various arch bridge suppliers
Summary and Quick Facts on CFFT Arch Bridges Innovative Product Application Rapid fabrication Hybrid composite-concrete system improves material performance Steel free superstructure Reduced carbon footprint Performance Tested Design/tested to exceed AASHTO load requirements Superior redundancy safe system Corrosion resistant materials Field load testing indicates even greater levels of safety Cost Effective and Fast Installation Light weight product reduces equipment transportation needs Erected with a small crew, no skilled labor Performs up to 2x lifespan of conventional materials Accelerated Bridge Construction Rapid design, fabrication, and delivery CONCRETE BRIDGES - CONCRETE SAVINGS.
Product AIT designs & manufactures FRP composite tubes for construction Ability to supply a complete engineered bridge system Packages: FRP arches + composite decking, modular FRP headwalls Structural Design AIT s engineers design the composite arch bridge superstructure Can design the bridge substructure, internally or with consultants Optimization to maximize efficiency of structure Local manufacturing and installation Carbon Fiber Bridge Superstructures Safe, Fast, Designed with Redundant Strength Characteristics Concrete Bridges Concrete Savings